This invention relates to a residual bobbin thread removing/eliminating device (hereinafter referred to as "a bobbin thread removing device", when applicable) used in an automatic bobbin thread feeding apparatus.
In the case where stitch lines of a sewing machine directly appear on a fabric or clothes, a look of a cloth is damaged by a partial stitch line created when a thread from a bobbin is exhausted. Therefore, the commercial value of the cloth goes down, particularly in case of a jacket or coat. If a partial stitch line occurs, additional labor is required to undo the partial stitch line and restitch the fabric from the beginning. To avoid such a waste of time, an operator has to monitor the thread of the bobbin at all times, and has to try to estimate the time when the thread from the bobbin will run out. Therefore, productivity is decreased, and further additional labor is are required.
To supply the thread continuously, a conventional thread feeding device is used. In the conventional thread feeding device, one bobbin in the needle position can be exchanged with another bobbin on which the thread is wound. However, the conventional thread feeding device can not remove the residual thread from the bobbin which is exchanged after the designated stitch operation. In this conventional thread feeding device, the operator must remove the thread from the bobbin by hand. Therefore, productivity is also decreased, and still further labor is required.